Using close-packed colloidal crystals-silica as the template,a novel 3D well-ordered and long-ranged periodic macroporous material MnO2 has been prepared by colloidal crystals template methods. The prepared product has been characterized by means of X-ray diffraction(XRD)and scanning electron micrography(SEM). The X-ray diffraction displays that the phase of MnO2 is tetragonal,and the scanning electron micrography shows that MnO2 replicates the structure of the started template and exhibits 3D long-range ordered honeycomb framework. The process of preparing the 3D order macroporous MnO2 was discussed. The effect of the infiltration times to the final morphology of MnO2 was studied and an abnormity existed in the shrinkage of the final outcome. 相似文献
Summary: Two kinds of stable colloidal crystals have been prepared from polymeric or SiO2 colloids in the presence of diazoresin (DR) as a thermosetting agent combining thermal treatment. Following the decomposition of Nequation/tex2gif-stack-1.gif groups of DR under heating, the ionic bonds between the DR molecules and colloids change to covalent bonds and the colloidal crystals become very stable toward ultrasonic washing. The colloids were then removed by tetrahydrofuran (THF) in the case of organics or by hydrofluoric acid (HF) for the inorganics to leave the macroporous DR materials.
Reactions between the DR molecules and the colloids during thermal treatment. 相似文献
Three-dimensionally ordered macroporous (3DOM) magnesium (Mg) oxide (MgO), MgSO4, calcium (Ca) carbonate (CaCO3), and strontium (Sr) carbonate (SrCO3) were prepared using a colloidal crystal of polymer spheres as a template. Ethanol or ethanol-water solution of metal salts (acetate or nitrate) and citric acid was infiltrated into the void of the colloidal crystal template of a monodispersed poly(methyl methacrylate) (PMMA) sphere. Heating of this PMMA-metal salt-citric acid composite produced the desired well-ordered 3DOM materials with a high pore fraction, which was confirmed by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ultraviolet-visible (UV-vis) diffuse reflectance spectra. The presence of citric acid is crucial for production of the 3DOM structures. Reaction of citric acid with metal salt produces metal citrate solid in the void of PMMA spheres, which is necessary to maintain the 3DOM structure during the calcination process. 3DOM CaCO3 shows opalescent colors because of it's photonic stop band properties. 相似文献